The Pentagon’s acquisition office for the F-35 Joint Strike Fighter expects to complete a plan and timeframe for conducting initial operational testing and evaluation (OT&E) of the stealth fighter jet by this fall, Vice Adm. David Venlet, the program manager, said this week.

Fully capable F-35s are expected to be ready by 2017 under the Block 3 version of the Lockheed Martin [LMT]-built airplane, but it would be up to the service chiefs to declare when the plane will achieve initial operational capability (IOC), Venlet said.

“The formal definition of IOC has more of a formality to it than it does the actual presence of aircraft with capabilities,” he said.

Venlet, speaking to reporters after Senate testimony on Tuesday, said he has been instructed by Pentagon acquisition chief Frank Kendall to produce plan for initial OT&E by September.

The nearly $400 billion Joint Strike Fighter program is the costliest acquisition program in the Pentagon’s history and has been the subject of strong criticism for massive cost overruns and delays. A recent Pentagon report put the total cost of 2, 443 planes, including operations and maintenance over their lifetime, at more than $1 trillion.

Venlet told the Senate Armed Services Committee aviation panel that with the restructuring of the program he is now confident the F-35 will start meeting schedule goals. He said the biggest challenge it now faces is maturing the software that operates the planes and their sensors and weapons.

“It is not that there is anything wrong with the software, it is the size of the task that gives us great concern,” he clarified to reporters after the hearing. He said it was a question of capacity of lab space, how much testing will be required and integrating its various components that is difficult.

On the labor dispute at Lockheed Martin’s Ft. Worth, Texas plant for manufacturing the F-35, Venlet said he does not expect the work stoppage to have a major impact on the program and was hopeful for a quick resolution. He noted that two F-35s are to be delivered this week.

“We look forward to a relatively small impact on the program,” Venlet said.